Gradient of the tangent to the curve question

[Hannelore]

Homework Statement

The point P (1/2, 0) lies on the graph of the curve of y=sin(2x-1) Find the gradient of the tangent to the curve of P

Homework Equations

...I don't know

The Attempt at a Solution

I don't know where to start with this problem

 

[Rainbow Child]

What is the geometrical interpretation of the derivative $$f'(x_o)$$ at the point $$(x_o,f(x_o))$$?